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Title "EVP_PKEY_CTX_ctrl 3"
way too many mistakes in technical documents.
The following functions have been deprecated since OpenSSL 3.0, and can be hidden entirely by defining OPENSSL_API_COMPAT with a suitable version value, see openssl_user_macros\|(7):
.Vb 1 #include <openssl/rsa.h> \& int EVP_PKEY_CTX_set_rsa_keygen_pubexp(EVP_PKEY_CTX *ctx, BIGNUM *pubexp); \& #include <openssl/dh.h> \& int EVP_PKEY_CTX_get0_dh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm); \& #include <openssl/ec.h> \& int EVP_PKEY_CTX_get0_ecdh_kdf_ukm(EVP_PKEY_CTX *ctx, unsigned char **ukm); .Ve
For cmd = EVP_PKEY_CTRL_SET_MAC_KEY, p1 is the length of the MAC key, and p2 is the MAC key. This is used by Poly1305, SipHash, HMAC and CMAC.
Applications will not normally call EVP_PKEY_CTX_ctrl() directly but will instead call one of the algorithm specific functions below.
\fBEVP_PKEY_CTX_ctrl_uint64() is a wrapper that directly passes a uint64 value as p2 to EVP_PKEY_CTX_ctrl().
\fBEVP_PKEY_CTX_ctrl_str() allows an application to send an algorithm specific control operation to a context ctx in string form. This is intended to be used for options specified on the command line or in text files. The commands supported are documented in the openssl utility command line pages for the option -pkeyopt which is supported by the \fIpkeyutl, genpkey and req commands.
\fBEVP_PKEY_CTX_md() sends a message digest control operation to the context \fIctx. The message digest is specified by its name md.
\fBEVP_PKEY_CTX_set_signature_md() sets the message digest type used in a signature. It can be used in the RSA, DSA and ECDSA algorithms.
\fBEVP_PKEY_CTX_get_signature_md()gets the message digest type used in a signature. It can be used in the RSA, DSA and ECDSA algorithms.
Key generation typically involves setting up parameters to be used and generating the private and public key data. Some algorithm implementations allow private key data to be set explicitly using EVP_PKEY_CTX_set_mac_key(). In this case key generation is simply the process of setting up the parameters for the key and then setting the raw key data to the value explicitly. Normally applications would call EVP_PKEY_new_raw_private_key\|(3) or similar functions instead.
\fBEVP_PKEY_CTX_set_mac_key() can be used with any of the algorithms supported by the EVP_PKEY_new_raw_private_key\|(3) function.
\fBEVP_PKEY_CTX_set_group_name() sets the group name to name for parameter and key generation. For example for EC keys this will set the curve name and for DH keys it will set the name of the finite field group.
\fBEVP_PKEY_CTX_get_group_name() finds the group name that's currently set with ctx, and writes it to the location that name points at, as long as its size namelen is large enough to store that name, including a terminating NUL byte.
Two RSA padding modes behave differently if EVP_PKEY_CTX_set_signature_md() is used. If this function is called for PKCS#1 padding the plaintext buffer is an actual digest value and is encapsulated in a DigestInfo structure according to PKCS#1 when signing and this structure is expected (and stripped off) when verifying. If this control is not used with RSA and PKCS#1 padding then the supplied data is used directly and not encapsulated. In the case of X9.31 padding for RSA the algorithm identifier byte is added or checked and removed if this control is called. If it is not called then the first byte of the plaintext buffer is expected to be the algorithm identifier byte.
\fBEVP_PKEY_CTX_get_rsa_padding() gets the RSA padding mode for ctx.
\fBEVP_PKEY_CTX_set_rsa_pss_saltlen() sets the RSA PSS salt length to saltlen. As its name implies it is only supported for PSS padding. If this function is not called then the maximum salt length is used when signing and auto detection when verifying. Three special values are supported:
\fBEVP_PKEY_CTX_get_rsa_pss_saltlen() gets the RSA PSS salt length for ctx. The padding mode must already have been set to RSA_PKCS1_PSS_PADDING.
\fBEVP_PKEY_CTX_set_rsa_keygen_bits() sets the RSA key length for RSA key generation to bits. If not specified 2048 bits is used.
\fBEVP_PKEY_CTX_set1_rsa_keygen_pubexp() sets the public exponent value for RSA key generation to the value stored in pubexp. Currently it should be an odd integer. In accordance with the OpenSSL naming convention, the pubexp pointer must be freed independently of the EVP_PKEY_CTX (ie, it is internally copied). If not specified 65537 is used.
\fBEVP_PKEY_CTX_set_rsa_keygen_pubexp() does the same as \fBEVP_PKEY_CTX_set1_rsa_keygen_pubexp() except that there is no internal copy and therefore pubexp should not be modified or freed after the call.
\fBEVP_PKEY_CTX_set_rsa_keygen_primes() sets the number of primes for RSA key generation to primes. If not specified 2 is used.
\fBEVP_PKEY_CTX_set_rsa_mgf1_md_name() sets the MGF1 digest for RSA padding schemes to the digest named mdname. If the RSA algorithm implementation for the selected provider supports it then the digest will be fetched using the properties mdprops. If not explicitly set the signing digest is used. The padding mode must have been set to RSA_PKCS1_OAEP_PADDING or RSA_PKCS1_PSS_PADDING.
\fBEVP_PKEY_CTX_set_rsa_mgf1_md() does the same as \fBEVP_PKEY_CTX_set_rsa_mgf1_md_name() except that the name of the digest is inferred from the supplied md and it is not possible to specify any properties.
\fBEVP_PKEY_CTX_get_rsa_mgf1_md_name() gets the name of the MGF1 digest algorithm for ctx. If not explicitly set the signing digest is used. The padding mode must have been set to RSA_PKCS1_OAEP_PADDING or \fBRSA_PKCS1_PSS_PADDING.
\fBEVP_PKEY_CTX_get_rsa_mgf1_md() does the same as \fBEVP_PKEY_CTX_get_rsa_mgf1_md_name() except that it returns a pointer to an EVP_MD object instead. Note that only known, built-in EVP_MD objects will be returned. The EVP_MD object may be NULL if the digest is not one of these (such as a digest only implemented in a third party provider).
\fBEVP_PKEY_CTX_set_rsa_oaep_md_name() sets the message digest type used in RSA OAEP to the digest named mdname. If the RSA algorithm implementation for the selected provider supports it then the digest will be fetched using the properties mdprops. The padding mode must have been set to \fBRSA_PKCS1_OAEP_PADDING.
\fBEVP_PKEY_CTX_set_rsa_oaep_md() does the same as \fBEVP_PKEY_CTX_set_rsa_oaep_md_name() except that the name of the digest is inferred from the supplied md and it is not possible to specify any properties.
\fBEVP_PKEY_CTX_get_rsa_oaep_md_name() gets the message digest algorithm name used in RSA OAEP and stores it in the buffer name which is of size namelen. The padding mode must have been set to \fBRSA_PKCS1_OAEP_PADDING. The buffer should be sufficiently large for any expected digest algorithm names or the function will fail.
\fBEVP_PKEY_CTX_get_rsa_oaep_md() does the same as \fBEVP_PKEY_CTX_get_rsa_oaep_md_name() except that it returns a pointer to an EVP_MD object instead. Note that only known, built-in EVP_MD objects will be returned. The EVP_MD object may be NULL if the digest is not one of these (such as a digest only implemented in a third party provider).
\fBEVP_PKEY_CTX_set0_rsa_oaep_label() sets the RSA OAEP label to binary data \fIlabel and its length in bytes to len. If label is NULL or len is 0, the label is cleared. The library takes ownership of the label so the caller should not free the original memory pointed to by label. The padding mode must have been set to RSA_PKCS1_OAEP_PADDING.
\fBEVP_PKEY_CTX_get0_rsa_oaep_label() gets the RSA OAEP label to \fIlabel. The return value is the label length. The padding mode must have been set to RSA_PKCS1_OAEP_PADDING. The resulting pointer is owned by the library and should not be freed by the caller.
\fBRSA_PKCS1_WITH_TLS_PADDING is used when decrypting an RSA encrypted TLS pre-master secret in a TLS ClientKeyExchange message. It is the same as RSA_PKCS1_PADDING except that it additionally verifies that the result is the correct length and the first two bytes are the protocol version initially requested by the client. If the encrypted content is publicly invalid then the decryption will fail. However, if the padding checks fail then decryption will still appear to succeed but a random TLS premaster secret will be returned instead. This padding mode accepts two parameters which can be set using the \fBEVP_PKEY_CTX_set_params\|(3) function. These are OSSL_ASYM_CIPHER_PARAM_TLS_CLIENT_VERSION and OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION, both of which are expected to be unsigned integers. Normally only the first of these will be set and represents the TLS protocol version that was first requested by the client (e.g. 0x0303 for TLSv1.2, 0x0302 for TLSv1.1 etc). Historically some buggy clients would use the negotiated protocol version instead of the protocol version first requested. If this behaviour should be tolerated then OSSL_ASYM_CIPHER_PARAM_TLS_NEGOTIATED_VERSION should be set to the actual negotiated protocol version. Otherwise it should be left unset.
\fBEVP_PKEY_CTX_set_dsa_paramgen_q_bits() sets the number of bits in the subprime parameter q for DSA parameter generation to qbits. If not specified, 224 is used. If a digest function is specified below, this parameter is ignored and instead, the number of bits in q matches the size of the digest.
\fBEVP_PKEY_CTX_set_dsa_paramgen_md() sets the digest function used for DSA parameter generation to md. If not specified, one of SHA-1, SHA-224, or SHA-256 is selected to match the bit length of q above.
\fBEVP_PKEY_CTX_set_dsa_paramgen_md_props() sets the digest function used for DSA parameter generation using md_name and md_properties to retrieve the digest from a provider. If not specified, md_name will be set to one of SHA-1, SHA-224, or SHA-256 depending on the bit length of q above. md_properties is a property query string that has a default value of '' if not specified.
\fBEVP_PKEY_CTX_set_dsa_paramgen_gindex() sets the gindex used by the generator G. The default value is -1 which uses unverifiable g, otherwise a positive value uses verifiable g. This value must be saved if key validation of g is required, since it is not part of a persisted key.
\fBEVP_PKEY_CTX_set_dsa_paramgen_seed() sets the seed to use for generation rather than using a randomly generated value for the seed. This is useful for testing purposes only and can fail if the seed does not produce primes for both p & q on its first iteration. This value must be saved if key validation of p, q, and verifiable g are required, since it is not part of a persisted key.
\fBEVP_PKEY_CTX_set_dsa_paramgen_type() sets the generation type to use FIPS186-4 generation if name is "fips186_4", or FIPS186-2 generation if name is "fips186_2". The default value for the default provider is "fips186_2". The default value for the FIPS provider is "fips186_4".
\fBEVP_PKEY_CTX_set_dh_paramgen_subprime_len() sets the length of the DH optional subprime parameter q for DH parameter generation. The default is 256 if the prime is at least 2048 bits long or 160 otherwise. The DH paramgen type must have been set to "fips186_4".
\fBEVP_PKEY_CTX_set_dh_paramgen_generator() sets DH generator to gen for DH parameter generation. If not specified 2 is used.
\fBEVP_PKEY_CTX_set_dh_paramgen_type() sets the key type for DH parameter generation. The supported parameters are:
The default in the default provider is DH_PARAMGEN_TYPE_GENERATOR for the "DH" keytype, and DH_PARAMGEN_TYPE_FIPS_186_2 for the "DHX" keytype. In the FIPS provider the default value is DH_PARAMGEN_TYPE_GROUP for the "DH" keytype and <DH_PARAMGEN_TYPE_FIPS_186_4 for the "DHX" keytype.
\fBEVP_PKEY_CTX_set_dh_paramgen_gindex() sets the gindex used by the generator G. The default value is -1 which uses unverifiable g, otherwise a positive value uses verifiable g. This value must be saved if key validation of g is required, since it is not part of a persisted key.
\fBEVP_PKEY_CTX_set_dh_paramgen_seed() sets the seed to use for generation rather than using a randomly generated value for the seed. This is useful for testing purposes only and can fail if the seed does not produce primes for both p & q on its first iteration. This value must be saved if key validation of p, q, and verifiable g are required, since it is not part of a persisted key.
\fBEVP_PKEY_CTX_set_dh_pad() sets the DH padding mode. If pad is 1 the shared secret is padded with zeros up to the size of the DH prime p. If pad is zero (the default) then no padding is performed.
\fBEVP_PKEY_CTX_set_dh_nid() sets the DH parameters to values corresponding to \fInid as defined in RFC7919 or RFC3526. The nid parameter must be \fBNID_ffdhe2048, NID_ffdhe3072, NID_ffdhe4096, NID_ffdhe6144, \fBNID_ffdhe8192, NID_modp_1536, NID_modp_2048, NID_modp_3072, \fBNID_modp_4096, NID_modp_6144, NID_modp_8192 or NID_undef to clear the stored value. This function can be called during parameter or key generation. The nid parameter and the rfc5114 parameter are mutually exclusive.
\fBEVP_PKEY_CTX_set_dh_rfc5114() and EVP_PKEY_CTX_set_dhx_rfc5114() both set the DH parameters to the values defined in RFC5114. The rfc5114 parameter must be 1, 2 or 3 corresponding to RFC5114 sections 2.1, 2.2 and 2.3. or 0 to clear the stored value. This macro can be called during parameter generation. The \fIctx must have a key type of EVP_PKEY_DHX. The rfc5114 parameter and the nid parameter are mutually exclusive.
\fBEVP_PKEY_CTX_set_dh_kdf_type() sets the key derivation function type to kdf for DH key derivation. Possible values are EVP_PKEY_DH_KDF_NONE and \fBEVP_PKEY_DH_KDF_X9_42 which uses the key derivation specified in RFC2631 (based on the keying algorithm described in X9.42). When using key derivation, the kdf_oid, kdf_md and kdf_outlen parameters must also be specified.
\fBEVP_PKEY_CTX_get_dh_kdf_type() gets the key derivation function type for ctx used for DH key derivation. Possible values are EVP_PKEY_DH_KDF_NONE and \fBEVP_PKEY_DH_KDF_X9_42.
\fBEVP_PKEY_CTX_set0_dh_kdf_oid() sets the key derivation function object identifier to oid for DH key derivation. This OID should identify the algorithm to be used with the Content Encryption Key. The library takes ownership of the object identifier so the caller should not free the original memory pointed to by oid.
\fBEVP_PKEY_CTX_get0_dh_kdf_oid() gets the key derivation function oid for ctx used for DH key derivation. The resulting pointer is owned by the library and should not be freed by the caller.
\fBEVP_PKEY_CTX_set_dh_kdf_md() sets the key derivation function message digest to \fImd for DH key derivation. Note that RFC2631 specifies that this digest should be SHA1 but OpenSSL tolerates other digests.
\fBEVP_PKEY_CTX_get_dh_kdf_md() gets the key derivation function message digest for \fIctx used for DH key derivation.
\fBEVP_PKEY_CTX_set_dh_kdf_outlen() sets the key derivation function output length to len for DH key derivation.
\fBEVP_PKEY_CTX_get_dh_kdf_outlen() gets the key derivation function output length for ctx used for DH key derivation.
\fBEVP_PKEY_CTX_set0_dh_kdf_ukm() sets the user key material to ukm and its length to len for DH key derivation. This parameter is optional and corresponds to the partyAInfo field in RFC2631 terms. The specification requires that it is 512 bits long but this is not enforced by OpenSSL. The library takes ownership of the user key material so the caller should not free the original memory pointed to by ukm.
\fBEVP_PKEY_CTX_get0_dh_kdf_ukm() gets the user key material for ctx. The return value is the user key material length. The resulting pointer is owned by the library and should not be freed by the caller.
\fBEVP_PKEY_CTX_set_ec_paramgen_curve_nid() does the same as \fBEVP_PKEY_CTX_set_group_name(), but is specific to EC and uses a nid rather than a name string.
For EC parameter generation, one of EVP_PKEY_CTX_set_group_name() or EVP_PKEY_CTX_set_ec_paramgen_curve_nid() must be called or an error occurs because there is no default curve. These function can also be called to set the curve explicitly when generating an EC key.
\fBEVP_PKEY_CTX_get_group_name() (described above) can be used to obtain the curve name that's currently set with ctx.
\fBEVP_PKEY_CTX_set_ec_param_enc() sets the EC parameter encoding to param_enc when generating EC parameters or an EC key. The encoding can be \fBOPENSSL_EC_EXPLICIT_CURVE for explicit parameters (the default in versions of OpenSSL before 1.1.0) or OPENSSL_EC_NAMED_CURVE to use named curve form. For maximum compatibility the named curve form should be used. Note: the \fBOPENSSL_EC_NAMED_CURVE value was added in OpenSSL 1.1.0; previous versions should use 0 instead.
\fBEVP_PKEY_CTX_get_ecdh_cofactor_mode() returns the cofactor mode for ctx used for ECDH key derivation. Possible values are 1 when cofactor key derivation is enabled and 0 otherwise.
\fBEVP_PKEY_CTX_get_ecdh_kdf_type() returns the key derivation function type for \fIctx used for ECDH key derivation. Possible values are \fBEVP_PKEY_ECDH_KDF_NONE and EVP_PKEY_ECDH_KDF_X9_63.
\fBEVP_PKEY_CTX_set_ecdh_kdf_md() sets the key derivation function message digest to md for ECDH key derivation. Note that X9.63 specifies that this digest should be SHA1 but OpenSSL tolerates other digests.
\fBEVP_PKEY_CTX_get_ecdh_kdf_md() gets the key derivation function message digest for ctx used for ECDH key derivation.
\fBEVP_PKEY_CTX_set_ecdh_kdf_outlen() sets the key derivation function output length to len for ECDH key derivation.
\fBEVP_PKEY_CTX_get_ecdh_kdf_outlen() gets the key derivation function output length for ctx used for ECDH key derivation.
\fBEVP_PKEY_CTX_set0_ecdh_kdf_ukm() sets the user key material to ukm for ECDH key derivation. This parameter is optional and corresponds to the shared info in X9.63 terms. The library takes ownership of the user key material so the caller should not free the original memory pointed to by ukm.
\fBEVP_PKEY_CTX_get0_ecdh_kdf_ukm() gets the user key material for ctx. The return value is the user key material length. The resulting pointer is owned by the library and should not be freed by the caller.
\fBEVP_PKEY_CTX_set_kem_op() sets the KEM operation to run. This can be set after \fBEVP_PKEY_encapsulate_init() or EVP_PKEY_decapsulate_init() to select the kem operation. RSA is the only key type that supports encapsulation currently, and as there is no default operation for the RSA type, this function must be called before EVP_PKEY_encapsulate() or EVP_PKEY_decapsulate().
The EVP_PKEY_CTX_set1_id(), EVP_PKEY_CTX_get1_id() and \fBEVP_PKEY_CTX_get1_id_len() macros were added in 1.1.1, other functions were added in OpenSSL 1.0.0.
In OpenSSL 1.1.1 and below the functions were mostly macros. From OpenSSL 3.0 they are all functions.
\fBEVP_PKEY_CTX_set_rsa_keygen_pubexp(), EVP_PKEY_CTX_get0_dh_kdf_ukm(), and EVP_PKEY_CTX_get0_ecdh_kdf_ukm() were deprecated in OpenSSL 3.0.
Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.